He was born in that part of Whitestown, then located in Montgomery County, which in 1792 was separated as the Town of Westmoreland, now in Oneida County, New York.
Chester Loomis attended school in Peterboro, New York, and afterwards became a clerk in Canandaigua.
On October 19, 1815, he married Hannah Hobart (1791–1865), and they had several children, among them Michigan State Senator Charles A. Loomis (1816–1898).
Chester Loomis was Postmaster of Rushville, New York, from 1818 to 1841.
In 1827, he was appointed an associate judge of the Ontario County Court.